Switch



July 1, 1930.

P. E. COOK SWITCH I 2 Sheets-Sheet 2 Filed Nov. 25. 1927 tnvenioflPatented July 1, 1930 UNITED STATES PATENT OFFICE) PERCY E. COOK, O1WARREN, OHIO, ASSIGNOR, BY'MESNE ASSIGNMENTS, T0 AMERICAN BROWN BOVERIELECTRIC CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK'HEISSUED Application filed November 23, 1927.' Serial No. 235,182.

This invention relates to im rovements in switches for transformers.rimarily the invention is a safety device, the object of Y one or moreof the others of the group, for,

'tion or the other.

even though the high tension side of a particular transformer bedisconnected from the high tension line, the high tension coil may beenergized by current flowing in the low tension coil. In other words,the trans-.- former then becomes a step up rather than a ste down thetransformer.

5116 of the objects of the present invention is the provision of meanswhich shall make it impossible for a workman or any one else to move theswitch while current is flowing in the low tension side of the line asthe result of induction in that particular transformer or any othertransformer of the group. The workman will, of course, not attempt toperform any operations upon the transformer with the switch in operativeposition, and if he cannot move it from that position he will know thatcurrent is passing through the transformer in either one direc- He willthen be forced to take the necessary steps to clear the transformerentirely.

, Another object is the provision of means for short-circuiting andgrounding the primar coil of the transformer, or of merely brea 'n'g thecircuit between the coil and the high voltage line.

A further object is the rovision of a magnetic lock for holding t eswitch in a given position whenever the secondary of the transformer isenergized.

Still another object is the provision of a switch mechanism of the kindreferred to, employing a plurality of sets of contacts, and bridgingmeans for said sets embodying a movable element and a magnetic lock forthe latter.

Other objects and features of novelty will appear as I proceed with thedescription of that embodiment of the invention which. for the purposesof the present application, I have illustrated in the accompanyingdrawings, in which Fig. 1 is a vertical central sectional view of anelectric switch apparatus embodying my invention;

Fig. 2 is an elevational view of that portion of the apparatus whichwould normally be located outside the wall or top of a transformer Fig.3 is a transverse sectional View taken substantially on line 33 of Fig.1;

Fig. 4 is a view of the selector cover which closes the opening in thetop of the casing of a transformer;

Fig. 5 is a vertical sectional detail view taken substantially on line5-5 of Fig. 1, and illustrating the magnetic lock;

Fig. 6 is a diagram of electric circuits illustrating the use of theinvention;

Fig. 7 is a cross sectional view of the magnetic lock, the view beingtaken substantially on the line 7-7 of Fig. 5;

Fig. 8 is a plan view of a locking ring used in carrying out theinvention;

Fig. 9 is a cross sectional detail view, this view also being takensubstantially on the line 33 of Fig. 1, and v Fig. 10 is a diagram of aslightly modified arran ement of electric circuits.

In t e drawings, a transformer top, which may be a casting, is indicatedfragmentarily at 10. Integral with the top are two or more dependingbosses 11 that receive fastenings 12 by means of which metal hangers 13are supported. The hangers 13 carry an insulating tube 15, which may bebuilt of fiber or other suitable material having good insulatingqualities. Angular contacts 16, 17, 18 and 19 (see Figs. 1 and 6) havetheir vertical legs shaped to fit the inner contour of the insulatingtube 15, and have their vertical legs secured thereto by studs 20 and 21which pass through openings formed in the wall of the tube. The studs 21are continued far enough beyond the wall of the tube to constitutebinding posts. Outside the tube 15 the binding posts of contacts 17 areconnected electrically, preferably by a copper bar or strap 22 whichextends upwardly and is joined to one of the hangers 13, as shown inFig. 1.

Arranged axially within the insulating tube 15 is a longitudinally androtatably movable element comprising rods 23, 24 and 25 formed ofsuitable lengths of insulating material. Laminated copper springs 26 and27 are interposed between the rods 23 and 24 and the rods 24 and 25,respectively, each spring being adapted to form a bridging connectionbetween the corresponding arcuate contact 16 and one of the contacts 1718, 19. These springs are mounted in arcuate clamps 28 and 29, each ofwhich is supplied with an integral hub portion 30 or 31 for thereception of one of the rods 23, 24, 25, suitable fastenings 32 beingset in the hubs and rods to hold them securely together.

The upper end of insulating rod 23 has attached thereto by means of afastening 33 a metallic extension 34 comprising a collar 35 and areduced upper portion 36. The latter portion has a sliding and rotatingfit within the hub of a plate 37 which I term a selector cover. Thiscover 37 closes an openng 38 in the top 10 of the transformer casng, agasket 39 being preferably interposed in order to maintain a moisturetight joint. The periphery of the cover 37 is provided With pairs ofspaced lugs 40 between which extend studs 41 that are threaded into thetop plate 10 and by means of which the cover is clamped in place. At theupper end of the hub or cover 37 I mount a packing gland 42 forexcluding moisture.

As may be seen best in Fig. 4, the cover 37 has a series of upwardlyextending arcshaped projections 43, 44 and 45 arranged in a circle, theprojections 43 and 44 having outwardly extending flanges 46 and 47,respectively, and the projection 43 having also a perforated lug 48.

The upper portion 36 of the movable switch element has a handle 49secured thereto by means of a pin 50. The lower part of the handle is inthe form of a sleeve 51 which encloses the hub of the cover 37 and thepacking gland 42. This sleeve at one point in its periphery and at itslower edge has an outwardly extending lug 52 which is adapted to fitwithin any of the three slots formed between the projections 43, 44 and45. When the lug 52 is positioned in any one of these slots it tends toremain there, due not only to gravity but also to pressure exerted by acoil spring 53 which bears at one end against lug 52. In the presentinstance this means consists of a locking ring 54, which surrounds thesleeve 51 and rides upon the tops of projections 43, 44 and 45, thisring being continuous except for an internal vertical groove 55 of asize sufficient to permit the projection '52 to move therein. Thelocking ring 54 may be rotated so as to bring the groove 55 intoregistration with any one of the slots between projections 43, 44 and45, and thus permit the lug 52 to be raised, after which the handle maybe rotated to turn the lug 52, carrying with it the locking ring 54 to aposition above one of the other slots, these slots corresponding, ofcourse, to the different positions of the springs 26 and 27. In one ofits angular positions the locking rin 54 is held against verticalmovement by 1100 r-shaped projections 56 and 57 which extend around andbeneath the projections 46 and 47 on the cover 37. In this same angularposition the groove 55 stands above the projection 44, that is out ofline with any of the slots between projections 43, 44 and 45. Thelocking ring is also provided with a perforated -lug 58 abutting in theposition named against the perforated lug 48 so that a padlock may bemounted in the perforations of the two lugs 48 and 58 to secure thelocking ring against rotation. By this means the handle 49 is securelylocked in any given position, preventing any unauthorized operation ofthe switch.

We will now consider the apparatus employed for automatically preventingthe operation of theswitch when current is passing in either directionthrough the transformer. on the lower end of rod 25 I secure, by meansof pins 60 and 61, a shoe 59 having a collar 62 at its lower extremity.This shoe slides within anopening in a casting 63 which bridges theopening at the lower end of the insulating tube 15. At one end of thecasting 63 there is supported an electromagnet core 64 of invertedU-shape, around one leg of which is mounted a coil 65. The casting 63includes a pair of depending arms 66, to the lower end of which ispivoted a bell crank 67. One arm of this bell crank carries an armature68adapted to bridge the ends of the core 64 of the electromagnet, and

the other arm carries a projection 69 which.

is adapted to overlap the collar 62 and prevent movement of the same.

Referring now to Fig. 6, the'wires of the high volta e sup 1y line areindicated at 70 and 71 an are s own connected to the contacts 19 of theupper and lower sets of contacts. The contacts 18 have no electricalconnections. The contacts 17 are shown joined together by the conductor22 which, as previously described, may consist of a copper strap asillustrated in Fig. 1. The conductor 22 also has a ground connectionthrough a conductor 13. The contacts 16 are joined by means ofconductors 72 and 73 with the ends ofthe high tension or primary coil 74of the transformer. The secondary coil 75 of the transformer has leadwires 76 and 77 extending therefrom which may have connections withother secondary coils of a network system. Shunted across the lead wires76 and 77 is the coil 65 of the electromagnet referred to above.

In Fig. 10, the electrical connections are such that instead ofshort-circuiting and grounding the primary coil of the transformer, Ishort-circuit and ground the incoming high tension supply lines, whichin this figure are numbered 7 0 and 71 and are shown connected with thelarge contacts 16. The primary coil in this instance is connected acrossthe contacts 19 by conductors 72 and 73. In other respects this figureis identical with Fig. 6.

\Vhenever there is current in the low ten sion line wires 76 and 77 theelectromagnet coil 65 is energized, lifting the armature 68 and rockingthe bell crank 67 to cause the projection 69 to overlap the collar 62and, prevent upward movement of the rod 25 and the other movableportions of the switch. In normal operation the switch springs 26 and 27bridge the two sets of contacts 16 and 19 connecting the supply lines70, 71 or 70', 71 with the transformer coil 74. When the contacts 16 and18 are bridged the supply lines are disconnected from the transformerand may be tested out for faults or may be put into service to carryother transformers. In the third position of Fig. 6, that is with thecontacts 16 and 17 bridged, the supply lines are disconnected and theprimary winding 74 of the transformer is simultaneously short-circuitedand grounded. In the third position as illustrated in Fig. 10, on theother hand, the primary circuit of the transformer is open i and thehigh tension feed line 70', 71

short-circuited and grounded.

Before any changes whatever can be made in the switch mechanism,however, the trans-.

former must be disconnected from the supply line by other means notherein shown, and in case there is low tension current in the conductors76, 77 due to action of other transformers in the network, then the coil75 must also be disconnected from the wires 76, 77. Otherwise theelectromagnet coil 65 will be energized and will lock the movable switchelement against upward movement. Following common practice in the artauto 'matic breakers may be employed in the cirswitch-by an unauthorizedperson may beprevented by the use of a padlock positioned in theperforated lugs 48 and 58, thus holding the locking ring 54 fromrotation and retaining the lug 52 in position in one of the slotsbetween projections 43, 44 and 45.

Obviously, the switch of the present invention may be used withtransformers other than those employed in an underground network system;the switch need not necessarily be mounted integral with the transformerbut may be separately housed; the switch in its different positions maymake connections other than those described above; more or less thanthree operating positions may be incorporated in the switch; and theswitch may be employed in connection with either single phase or threephase circuits.

Having thusdescribed my invention, what I claim is:

1. In combination, a transformer, a switch in the high tension side ofthe line comprising a contact which swings in moving from one positionto another, a longitudinally movable support for said contact, meansnecessitating the longitudinal movement of the support prior to theswinging of said contact, and electromagnetic means located in the lowtension side of the line for preventing the actuation of the switch.

2. In combination, a transformer, a switch for the high tension side ofthe line com prising a longitudinally displaceable rod, a contact armextending outwardly from said rod, means necessitating the longitudinalmovement of the rod prior to the swinging of said arm, andelectromagnetic means located in the low tension side of the line forpreventing the longitudinal movement of the rod when saidelectromagnetic means is energized.

3. In combination, a transformer, a casing therefor, a switch for thehigh tension si e of the line comprising a rod extending through saidcasing, a contact arm extending outwardly from saidirod within saidcasing, a plurality of fixed contacts within the casin adapted to beengaged by said arm simu taneously, means necessitating the longitudinalmovement of the rod prior to the swinging of said arm to engage ordisengage said contacts, a handle for the rod outside said casing, andelectromagnetic means within the casing located in the low tension sideof the line for preventing the longitudinal movement of the rod.

4. In combination, a transformer, a casing therefor, a switch for thehigh tension transformer, a second pair of fixed contacts side of theline comprising a rod extending through said casing, a contact armmounte u on said rod within the casing, a-plurahty o? fixed contactswithin the casing adapted to be engaged. by said arm simultaneously,

a spring tending to move said rod 1ongitudinally and hold it in adjustedposition, and electromagnetic means in the casing located in the lowtension side of the line for holding the rod in adjusted position.

5. In combination, a transformer, a switch therefor comprisin a pair offixed contacts connected across t e primary coil of the connected withthe high tension line, and a third pair of fixed contacts connectedtoether, two movable switch arms ada ted to ridge each of the contactsof one pair with the lndividual contacts of one of the other pairs, andmeans for preventing the movement of said switch arms so long as thereis current in the low tension coil of the transformer.

6. In combination, a transformer, a switch therefor com rising" alongitudinally movable rod, locl ing means for said rod normally heldout of operative position, and electromagnetic means for moving saidlocking means into operative position, said last named means beincontrolled by current in the low tension si e of the line.

7. In an electrical system, an electrical supply line, a transformer,switch means operable to provide for connection and dis-.

connection of said transformer with respect to said line, said switchmeans including a switch member supported for movement in differentdirections, means operable to preventmovement of said member in one ofsaid directions independently of movement of the same first in anotherof said directions, means operable to lock said member against movementin said last-mentioned direction, and means responsive to operatingconditions of said transformer and operable upon occurrence of suchconditions to hold said locking means .in looking position.

In testimony whereof, I hereunto aflix my signature.

PERCY E. COOK.

